Analysis, Critique and Suggested Modification

for the Proposed Improvements to Downtown Freeways and I-45 North

• The connection ramp between the SH 288 toll lanes and Chenvert Street has been eliminated. The existing freeway has connections between the SH 288 main lanes and Chenevert, so the Chenevert connection was not a new feature. In the May 2018 schematic, the northbound SH 288 toll lane terminates into the connector to IH 45, and the entrance into the southbound toll lane is from the southbound frontage road.
• The design of the downtown connector has been altered at West Dallas Street. In the May 2017 schematic the downtown connector went over West Dallas. In the May 2018 design the downtown connector goes below grade underneath West Dallas. This change necessitated the elimination of the smooth transition from the northbound connector frontage road to Houston Avenue; northbound frontage road traffic must now make a left turn on West Dallas, cross over the connector main lanes, and the make a right turn on the road which becomes Houston Avenue.
• On the east side of downtown adjacent to the convention center, the exit from southbound IH 69 to Bell Street now has two lanes.

Detailed Analysis Prepared by a HoustonFreeways.com Reader

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This item has existed on all prior versions of the schematics. But I still believe there is a need for at least one additional northbound entrance inside the loop, and there are potentially feasible options to be considered.

Problem

• There is only ONE definite access point to the northbound managed lanes inside the loop, from Travis Street downtown. The May 2017 plan shows a potential connection from the IH 10 eastbound express lanes.
• Traffic on the northbound IH-45 main lanes, northbound on the downtown spur and westbound on IH-10 cannot get on the managed lanes until the entrance at the North Loop.
• Since there is normally a heavy traffic backup inside the Loop between downtown and Loop 610, motorists should have the option of better access to the managed lanes to avoid the traffic jams

Potential Solution

• Ideally, both the northbound downtown Spur and IH-45 northbound main lanes should have access to the managed lanes in the downtown area.
• It appears to be feasible to add access to the northbound managed lanes from both the IH 45 northbound main lanes and the northbound Spur. See the diagrams below.
• If both options above are not feasible or not cost-effective, shifting the northbound managed lanes access point to the area south of Patton as suggested in item 2 would help mitigate this problem, and may in fact be the best solution since it would also solve design concern #2.

The plan also lacks a connection from the southbound managed Lanes to the southbound downtown Spur. I feel that connection is less urgent because main lane backups are more likely in the northbound direction.

Outlook

• The May 2017 schematics did not provide any improvement for this situation while making many other changes in this area of the project. The May 2018 schematics included no changes in this area of the project. Since the additional connections (such as the ramps I am suggesting) will be expensive, I'm thinking that changes to address this concern are unlikely.

This image shows how a connection from the northbound IH 45 main laness to the northbound MaX lanes can be added.
This image shows how a connection from the northbound downtown Spur to the northbound MaX lanes can be added. Back to top

Due to constricted right-of-way width in this section, the design standards are compromised. Because the west side of the freeway is lined with lower-tier commercial establishments and some vacant lots, it makes no sense to constrict the width and introduce design compromises.

Problem

• The managed (MaX) lanes don't have a dedicated shoulder due to the constricted right-of-way width
• It is unclear from the schematics if there is an adequate merging zone for the northbound entrance ramp just south of Main Street. Ideally an auxiliary lane should be maintained for a distance, possibly all the way to the Loop 610 exit.
• The merging distance for the southbound entrance ramp from Cavalcade also appears to be very short.

Potential Solution

• Ideally, the right-of-way width should be widened to provide standard-width shoulders for both the main lanes and the MaX lanes.
• Add a northbound auxiliary lane for at least a short distance for the northbound entrance ramp just south of Main Street, and a southbound auxiliary lane for at least a short distance for the southbound on-ramp from Cavalcade.
• Consider using extra right-of-way on the west side which is currently listed as a potential detention area. Replacement detention acreage can be obtained around the truck stop.

Outlook

• Due to the right-of-way restrictions, the chance for fixing these issues was low. Since the May 2018 schematic was unchanged from the May 2017 schematic, it is assumed that the current design is unlikely to change. However, maybe a future re-evaluation will ensure there is sufficient merging distance on the two entrance ramps (northbound south of Main, and southbound from Cavalcade.)

Problem

• There are six lanes of traffic going westbound including the Loop 610 main lanes and lanes on the connections from IH 45, and these six lanes are reduced to four lanes in too short a distance
• This is similar to the present-day situation, where the merging transition zone is too short.

Potential Solution

• Extend the transition zone by adding a westbound auxiliary lane over Main and Yale.

Outlook

• The May 2018 schematic was unchanged from the May 2017 schematic. This could potentially be considered in a re-evaluation, but my suggestion will extend the project scope westward along Loop 610, which may be a nonstarter.

Problem

• There appears to be little or no merging zone for the on-ramp from Quitman
• The merge zone into the northbound IH 45 main lanes appears to be short or non-existent
• The merge zone into the northbound IH 45 main lanes is at the tunnel entrance, and changing lighting conditions may cause additional motorist distraction and stress, potentially making this a dangerous on-ramp if there is not a dedicated auxiliary lane.

Potential Solution

• The on-ramp from Quitman should have a dedicated lane
• The merge into the IH 45 northbound main lanes should have an auxiliary lane, and at the minimum a sufficient transition zone

Outlook

• The May 2018 schematic was unchanged from the May 2017 schematic. The concern about the merge zone with the on-ramp from Quitman should be easy to fix at minimal cost, so I'm still hopeful. Extending the merging zone with the main lanes may be technically infeasible, but I'm still concerned about a short merge zone right at the tunnel entrance.

Problem

• On the connection ramp from Beltway 8 to IH 45 southbound, there is only one lane connecting to the IH 45 regular main lanes
• The transition/merging zone of the lane coming from Beltway 8 is too short

Potential Solution

• Have two lanes from the Beltway 8 connection ramp connect to the main lanes
• One lane should exit to West Road
• The second lane should continue as an extended auxiliary lane across West Road
• Additional changes in this area are needed to fix the short frontage road merge distance for the exit/entrance ramp, see issue 8

Outlook

I previously raised this issue in 2016 and the May 2017 update did not improve this situation. The May 2018 schematic was unchanged from the May 2017 schematic. I still think this is a serious design concern which will cause backups on the ramp from BW8. While fixing this issue will have a non-trivial cost, it is probably the most cost-effective and feasible fix of all the issues in my list.

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I experience an excessively short frontage road merging zone on a daily basis on the Southwest Freeway southbound exit ramp to Beechnut, which has a lane weave zone only 1000 feet long, not nearly long enough and usually a stressful merge. Two frontage road transition zones planned for Interstate 45 are less than 1000 feet.

Problem

The length of the auxiliary lane on the frontage road between exits ramps and entrance ramps are short in these locations

• Southbound, between West Road and Fallbrook, about 600 feet
• Southbound, between Little York and Parker, about 900 feet
• Southbound, between Yale and Tidwell, about 1600 feet
• Northbound, between Parker and Little York, about 1400 feet

Potential Solution

• Adjust ramp locations to lengthen the frontage road transtion zones
• Braided ramps could be warranted in both directions between Parker and Little York
• The southbound ramp north of West Road may need major rearrangement in conjunction with a fix for the issue with the lanes from the Beltway 8 ramp. I'm thinking that the on-ramp should be included in the ramp to the MaX lanes, but then the currently-planned ramp will have a split point where traffic chooses between the MaX lanes and the main lanes (see diagram).

Outlook

In 2018 there were no changes to project north of Loop 610, and TxDOT did not post a revised schematic. These concerns are minor issues and may not warrant costly braided ramps, so I'm not expecting changes at these locations.

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Entrance ramps without a dedicated lane (and associated long merge zone) can cause traffic slow-downs and are a higher risk for accidents. That's why the existing freeway between Shepherd and Beltway 8 was restriped (with the interior shoulder eliminated) a few years ago to provide a dedicated lane for each on-ramp.

Problem

• There is no dedicated lane for the onramp going northbound from Airline, which is a more difficult situation for motorists and also is a cause of traffic slow-downs
• The Airline on-ramp is the first northbound onramp north of the Loop, 1.7 miles north of the Loop, so it should have significant traffic count
• The lane the on-ramp merges into exits in about 1700 feet, forcing motorists to make a second lane switch/merge after the initial merge.

Potential Solution

• Include a dedicated lane for the on-ramp, which would add one lane to the freeway going over Tidwell.
• Continue the fifth main lane past the exit to Parker
• Ideally the fifth main lane will continue further north, perhaps to Shepherd, but it can also be merged into the main lanes after about 2000 feet before the next on-ramp.

Outlook

In 2018 there were no changes to project north of Loop 610. There appears to be sufficient space available for the extra lane at the Tidwell overpass, and there is definitely space available north of Tidwell, so adjustments in this area should be feasible.

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Problem

• Southbound IH 69 traffic connecting to southbound IH 45 must move three lanes to the left in 2200 feet. Traffic coming from the ramp on the left side will also be moving to the right, causing a weaving zone.
• This will be in the tunnel just after entering the tunnel, and people's vision will be adjusting during the day, probably causing some delay in response time, making the connection more stressful for motorists.
• In my experience, viewing signage and changing lanes in a tunnel is more difficult than outside of a tunnel, which is another reason to move this connection outside of the tunnel.

Potential Solution

• Move the connection northward (see diagram). Ideally an auxiliary lane should be maintained on IH 45 southbound, but if an auxiliary lane won't fit, I still think it will be better for motorists to move the connection north.
• The existing connection should be maintained to serve traffic coming from IH 10 which needs to connect to IH 45 southbound.

Outlook

I still don't like the idea of having a weaving zone inside the tunnel, and I felt this was an easy issue to fix. The May 2018 schematic was unchanged from the May 2017 schematic. This is a difficult area for design due to the limited right-of-way, so I'm thinking that future changes are unlikely.

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Problem

• Vehicles connecting from IH 45 northbound to IH 69 southbound may try to exit to Almeda, making a five-lane weave to the right in 1900 feet.
• Traffic entering the freeway from the Webster Street on-ramp will be moving to the left, creating a weave zone.

Potential Solution

• There appears to be no feasible way to prevent the 5-lane weave from the ramp from IH 45. And maybe only a small percentage of vehicles will attempt to reach the Almeda exit
• The best solution is to minimize the number of vehicles attempting to exit to Almeda. Restoring the exit ramp to Fannin will provide another option for vehicles looking to reach the Midtown area. Without the Fannin exit, it will be 2.3 miles to the next exit at Shepherd, and this long distance will surely cause vehicles from IH 45 to try to reach the Almeda exit.

Outlook

This was another reason to restore the exit to Fannin. But since the May 2018 schematic was unchanged from the May 2017 schematic, it is assumed that the restoration of the exit at Fannin is unlikely.

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Problem

• The right lane of the two lanes coming from SH 288 must move to the left
• IH 69 northbound traffic exiting to Gray Street will be moving to the right
• The merge/weave zone is only around 1500 feet, about the same that exists today, and the lane weaving will be about the same as exists today

Potential Solution

• Since the SH 288 lanes go over Alabama Street, there is a geomtric constraint since the lanes must drop about 45 feet
• Move the merge point as far south as possible, possibly by using slim beams on the Alabama overpass and also possibly by a design exception of downgrade percent. A steeper than usual downgrade is preferable to a short and dangerous merging zone.
• The westbound Woodall Rodgers Freeway in Dallas has an 8% downgrade for a similar drop, with no negative effect.
• By using a 4% downgrade after the Alabama overpass, the connection ramp can be dropped 45 feet in about 1100 feet, which would increase the weave zone length by 500 feet.

Outlook

The May 2018 schematic was unchanged from the May 2017 schematic. My concern at this location may not be warranted by technical standards, and is more of a "nice-to-have". So I'm not expecting future changes relating to this concern.

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There is normally traffic congestion south of Loop 610 due to this bottleneck location. The managed lanes will help with this problem, but the managed lanes have poor access in the current plan (see item 3 above).

Problem

• IH-45 Northbound is reduced to three main lanes at Loop 610
• Access to the northbound Max lanes is poor, so most motorists won't be able to bypass backups using the MaX lanes

Potential Solution

• Maintain four northbound main lanes across Loop 610
• The northbound entrance ramp from the frontage road just south of Loop 610 would not have a dedicated lane

Outlook

The May 2018 schematic was unchanged from the May 2017 schematic. This location is more affected by issue 3, so I'm hopeful that future adjustments relating to issue 3 may also help with this item.

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